Oxyhalogenation process using catalyst having porous rare earth halide support

ABSTRACT

An oxidative halogenation process involving contacting a hydrocarbon, for example, ethylene, or a halogenated hydrocarbon with a source of halogen, such as hydrogen chloride, and a source of oxygen in the presence of a catalyst so as to form a halocarbon, preferably a chlorocarbon, having a greater number of halogen substituents than the starting hydrocarbon or halogenated hydrocarbon, for example, 1,2-dichloroethane. The catalyst is a novel composition comprising copper dispersed on a porous rare earth halide support, preferably, a porous rare earth chloride support. A catalyst precursor composition comprising copper dispersed on a porous rare earth oxyhalide support is disclosed. Use of the porous rare earth halide and oxyhalide as support materials for catalytic components is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divsional of U.S. application Serial No.10/130,107 filed May 14, 2002, now allowed, which is a 371 continuationof PCT Application PCT/US00/31490 filed Nov. 16, 2000, which claims thebenefit of U.S. Provisional Application No. 60/166,897, filed Nov. 22,1999.

BACKGROUND OF THE INVENTION

[0002] In a first aspect, this invention pertains to a process ofoxidative halogenation, particularly oxidative chlorination. For thepurposes of this discussion, the term “oxidative halogenation” isdefined as a process wherein a hydrocarbon or halogenated hydrocarbon(the “starting hydrocarbon”) is contacted with a source of halogen and asource of oxygen so as to form a halocarbon having a greater number ofhalogen substituents than the starting hydrocarbon. The term“halocarbon” will include halogenated hydrocarbons as well as compoundsconsisting only of carbon and halogen atoms. In a second aspect, thisinvention pertains to a novel catalyst for the oxidative halogenationprocess. In a third aspect, this invention pertains to novel catalystsupports.

[0003] Halogenated hydrocarbons, such as 1,2-dichloroethane,1,2-dibromoethane, dichloropropanes, and dichloropropenes, find utilityin numerous applications, such as in fumigants and in the production ofmonomers useful in polymerization processes. 1,2-Dichloroethane, forexample, which is manufactured industrially on a scale of severalmillion tons per year, is converted by thermal dehydrochlorination intovinyl chloride monomer(VCM) and hydrogen chloride. VCM is polymerizedinto poly(vinyl)chloride (or PVC), a widely used polymer. The hydrogenchloride produced by dehydrochlorination is separated from the VCM andthereafter contacted with ethylene and oxygen in the presence of acatalyst to produce 1,2-dichloroethane. In the prior art, the contactingspecifically of ethylene, hydrogen chloride, and oxygen to form1,2-dichloroethane and water is known as the “oxychlorination reaction.”

[0004] The oxychlorination of ethylene is abundantly described in thepatent literature, representative art of which includes U.S. Pat. No.3,634,330, U.S. Pat. No. 3,658,367, U.S. Pat. No. 3,658,934, U.S. Pat.No. 5,972,827, GB 1,039,369, and GB 1,373,296. The catalyst employed inthe oxychlorination of ethylene typically contains copper chloride oriron chloride, and optionally, one or more alkali or alkaline earthmetal chlorides, and/or optionally, one or more rare earth chlorides,supported on an inert carrier, typically alumina, silica, or analuminosilicate. Alternatively, the catalyst components can beunsupported, but fused into a molten salt.

[0005] Oxidative halogenation processes are quite general and can beextended to a variety of hydrocarbons in addition to ethylene. Forexample, oxidative chlorination processes are known for the conversionof methane to chloromethanes, ethane to chloroethanes and chloroethenes,and, by analogy, higher saturated hydrocarbons to higherchlorohydrocarbons. This chemistry is not unique to chlorine and canalso be extended broadly to other halogens. Halogen sources can comprisehydrogen halides and halohydrocarbons having labile halogens.

[0006] One disadvantage of prior art oxidative halogenation processesinvolves their production of undesirable oxygenated by-products, such aspartially oxidized hydrocarbons and deep oxidation products (CO_(x)),namely, carbon monoxide and carbon dioxide. Another disadvantage ofprior art oxidative halogenation processes involves their production ofundesirable oxygenated halocarbon by-products, for example,trichloroacetaldehyde (also known as chloral, CCl₃CHO) in the productionof 1,2-dichloroethane. The production of unwanted by-productsirretrievably wastes the hydrocarbon feed and creates product separationand by-product disposal problems. Any reduction in the quantity ofoxygenated products, particularly, oxygenated halocarbons and CO_(x)oxygenates would be highly desirable.

[0007] In a different aspect, rare earth compounds are known to bepromoters in a diverse assortment of catalyzed organic processes,including, for example, oxidations, steam reforming, auto emissionreduction, esterification, Fischer-Tropsch synthesis, and theaforementioned oxidative halogenation processes. In the generalpreparation of rare earth-promoted catalysts, a solution containing asoluble rare earth salt, such as the chloride, is dispersed, forexample, by impregnation or ion-exchange, optionally, along with one ormore additional catalytic components onto a support or carrier, such asalumina or silica. U.S. Pat. No. 2,204,733 discloses a catalystcontaining a compound of copper and a compound of the rare earth group,being prepared by precipitating the metals as hydroxides onto a suitablesupport, or by soaking or impregnating a support with a solution ofcopper and rare earth salts, or by precipitating the metals ashydroxides with sodium or potassium hydroxide. The art, in general,appears to be silent with respect to rare earth compounds functioning ascatalyst carriers or supports, perhaps because rare earth compoundstypically are not found to be porous. Catalyst supports are generallyknown to require at least some porosity, that is, some void space, suchas channels and pores or cavities, which create surface area whereoncatalytic metals and components can be deposited.

SUMMARY OF THE INVENTION

[0008] In one aspect, this invention is a novel oxidative halogenationprocess of preparing a halocarbon. The novel process of this inventioncomprises contacting a hydrocarbon or halogenated hydrocarbon with asource of halogen and a source of oxygen in the presence of a catalystunder process conditions sufficient to prepare a halocarbon containing agreater number of halogen substituents than in the starting hydrocarbonor halogenated hydrocarbon, as the case may be, the catalyst comprisingcopper on a porous rare earth halide support. The term “halocarbon” willbe understood as including halogenated hydrocarbons as well as compoundsconsisting only of carbon and halogen atoms.

[0009] The oxidative halogenation process of this inventionadvantageously converts a hydrocarbon or halogenated hydrocarbon in thepresence of a source of halogen and a source of oxygen into a halocarbonhaving an increased number of halogen substituents as compared with thestarting hydrocarbon. Accordingly, the process of this invention can beused, in a preferred embodiment, to oxychlorinate ethylene in thepresence of hydrogen chloride and oxygen into 1,2-dichloroethane. Sincethe hydrogen chloride may be derived from the dehydrochlorination of1,2-dichloroethane, the process of this invention may be easilyintegrated into a VCM plant, as described hereinabove. As a morepreferred advantage, the process of this invention produces lower levelsof undesirable by-products, particularly CO_(x) oxygenates, namely,carbon monoxide and carbon dioxide, and lower levels of undesirableoxygenated halocarbons, such as chloral, than prior art oxidativehalogenation processes. The reduction in undesirable oxygenatedby-products translates into a higher selectivity to the desiredhalocarbon product, lower waste of hydrocarbon feed, and fewerby-product disposal problems. In addition, the better selectivity to thedesired halocarbon product allows the process to be operated at highertemperatures for higher conversion.

[0010] In a second aspect, this invention is a novel composition ofmatter comprising copper dispersed on a porous rare earth halidesupport.

[0011] The novel composition of this invention is useful as a catalystin the oxidative halogenation of hydrocarbons or halogenatedhydrocarbons, as exemplified by the oxychlorination of ethylene in thepresence of a source of chlorine and oxygen to form 1,2-dichloroethane.Advantageously, the novel catalyst of this invention produces lowerlevels of by-products, particularly CO_(x) oxygenates and oxygenatedhalocarbons, such as chloral, in the aforementioned oxidativehalogenation process. As a second advantage, the unique catalystcomposition of this invention does not require a conventional carrier orsupport, such as alumina or silica. Rather, the catalyst of thisinvention employs a porous rare earth halide, which uniquely functionsboth as the catalyst's support and as a source of a furthercatalytically active (rare earth) component.

[0012] In a third aspect, this invention is a second composition ofmatter comprising copper dispersed on a porous rare earth oxyhalidesupport. This second novel composition is a useful catalyst precursor tothe catalyst comprising copper dispersed on the porous rare earth halidesupport, described hereinabove.

[0013] In a fourth aspect, this invention claims use of theaforementioned porous rare earth oxyhalide and porous rare earth halideas supports and carriers for catalytic components. The porous rare earthoxyhalide or rare earth halide can be used as a support for anycatalytic metal or metallic ion in the Periodic Table of the Elements,as well as any organic or non-metallic inorganic catalyst component.

[0014] The porous rare earth oxyhalide or halide support can beadvantageously employed in catalysts which benefit from the promotingeffects of rare earth elements and/or in catalysts which requirebasicity. Unlike most catalyst supports of the prior art, the rare earthhalide support of this invention is soluble in water. Accordingly,should process equipment, such as filters, valves, circulating tubes,and small or intricate parts of reactors, become plugged with particlesof a catalyst containing the rare earth halide support of thisinvention, then a simple water wash can advantageously dissolve theplugged particles and restore the equipment to working order. As afurther advantage, the novel rare earth halide and oxyhalide supports ofthis invention provide for the easy recovery of costly catalytic metals.The recovery simply involves contacting the spent catalyst containingthe catalytic metals and the novel support with acid under conditionssufficient to etch away the catalytic metals. Thereafter, the metals canbe recovered from the acidic medium, for example, by precipitation. Anyportion of the rare earth support dissolved into the acidic medium canalso be recovered by re-precipitation with base.

DETAILED DESCRIPTION OF THE INVENTION

[0015] In the novel oxidative halogenation process of this invention, ahalocarbon is produced selectively with advantageously low levels ofby-products, such as, CO_(x) oxygenates (CO and CO₂) and oxygenatedhalocarbons, such as, chloral. The novel process of this inventioncomprises contacting a hydrocarbon or halogenated hydrocarbon (the“starting hydrocarbon”) with a source of halogen and a source of oxygenin the presence of a catalyst under process conditions sufficient toprepare a halocarbon having a greater number of halogen substituentsthan the starting hydrocarbon. As mentioned hereinbefore, for thepurposes of this invention, the term “halocarbon” includes halogenatedhydrocarbons, such as 1,2-dichloroethane, as well as compoundsconsisting only of carbon and halogen atoms, such as perchloroethylene.

[0016] In a preferred embodiment, the process of this invention is anoxidative chlorination process comprising contacting a hydrocarbon orchlorinated hydrocarbon with a source of chlorine and a source of oxygenin the presence of a catalyst under conditions sufficient to prepare achlorocarbon having a greater number of chloro substituents than in thestarting hydrocarbon. In a most preferred embodiment of this invention,the hydrocarbon is ethylene, and the chlorocarbon is 1,2-dichloroethane.

[0017] The novel catalyst employed in the oxidative halogenation processof this invention comprises copper dispersed on a porous rare earthhalide support. For the purposes of this invention, porosity isexpressed in terms of surface area. In a preferred embodiment, theporous rare earth halide support has a surface area of least 5 m²/g, asdetermined by the BET (Brunauer-Emmet-Teller) method of measuringsurface area, as described by S. Brunauer, P. H. Emmett, and E. Teller,Journal of the American Chemical Society, 60, 309 (1938). In a preferredembodiment, the porous rare earth halide support comprises a porous rareearth chloride.

[0018] In another aspect, this invention is a second composition ofmatter comprising copper dispersed on a porous rare earth oxyhalidesupport. This second composition functions as a catalyst precursor,which finds utility in the preparation of the aforementioned rare earthhalide catalyst. In a preferred embodiment, the porous rare earthoxyhalide support has a surface area of least 12 m²/g, as determined bythe BET method. In a more preferred embodiment, the porous rare earthoxyhalide support comprises a rare earth oxychloride.

[0019] In yet another aspect, this invention claims the use of theaforementioned porous rare earth oxyhalide and porous rare earth halideas a support or carrier for catalytic components.

[0020] Hereinafter, the description will be drafted towards thepreferred process of oxidative chlorination; however, in light of thedetailed description set forth, one skilled in the art will be able toextend the description to oxidative halogenations other than oxidativechlorination.

[0021] The hydrocarbon used in the oxidative chlorination process ofthis invention may be any hydrocarbon which is capable of acquiringhalogen substituents in accordance with the process of this invention.The hydrocarbon may be an essentially pure hydrocarbon or a mixture ofhydrocarbons. The hydrocarbon may be C₁₋₂₀ aliphatic hydrocarbons,including C₁₋₂₀ alkanes or C₂₋₂₀ alkenes, as well as C₃₋₁₂cycloaliphatic hydrocarbons, or C₆₋₁₅ aromatic hydrocarbons. Suitablenon-limiting examples of such hydrocarbons include methane, ethane,propane, ethylene, propylene, butanes, butenes, pentanes, pentenes,hexanes, hexenes, cyclohexane and cyclohexene, as well as benzene andother C₆₋₁₅ aromatics, such as naphthalenes. More preferably, thehydrocarbon is selected from C₁₋₂₀ aliphatic hydrocarbons, even morepreferably, from C₂₋₁₀ alkenes, and most preferably, ethylene.

[0022] It is further within the scope of this invention for thehydrocarbon feed to be substituted with one or more halogensubstituents. Preferably, however, the substituted hydrocarbon retainsat least one or more carbon-hydrogen bonds; but as noted hereinbelow,certain halocarbons that do not contain carbon-hydrogen bonds, such as(perhalo)olefins, may also be suitable. Preferred halogen substituentsinclude fluorine, chlorine, and bromine. More preferred, are fluorineand chlorine. As an example, the starting halogenated hydrocarbon can bea fluorohydrocarbon which is converted via the oxidative chlorinationprocess of this invention into a chlorofluorocarbon. In an alternativeembodiment, a (perfluoro)olefin can be employed as the starting materialand converted into a chlorofluorocarbon.

[0023] The source of chlorine, which is employed in the process of thisinvention, can be any chlorine-containing compound, which is capable oftransferring its chlorine to the hydrocarbon feed and providing a sourceof hydrogen to the oxygen feed. Suitable non-limiting examples of thesource of chlorine include hydrogen chloride and any chlorinatedhydrocarbon having one or more labile chlorine substituents (that is,transferable chloro substituents), a non-limiting example of which ismethylene dichloride. Typically, molecular chlorine (Cl₂) is notemployed in the process of this invention, which requires a source ofoxygen and produces water. Preferably, the source of chlorine ishydrogen chloride.

[0024] The source of chlorine may be provided to the process in anyamount which is effective in producing the desired chlorocarbon product.Typically, the source of chlorine is used in an amount equal to thestoichiometric amount required by the oxidative chlorination reaction ofinterest. In the oxychlorination of ethylene with hydrogen chloride andoxygen, for example, the theoretical stoichiometry is the following:

2CH₂=CH₂+4HCl+O₂→2CH₂Cl—CH₂Cl+2H₂O

[0025] Consequently, in ethylene oxychlorination according to thisinvention, typically four moles of hydrogen chloride are employed permole of oxygen. The hydrogen chloride and oxygen are employed in amountswhich are ideally selected to facilitate the near complete reaction ofboth reagents; but greater and lesser amounts of hydrogen chloride mayalso be found suitable.

[0026] The source of oxygen can be any oxygen-containing gas, such as,commercially pure molecular oxygen, or air, or a mixture of oxygen inanother diluent gas which does not interfere with the oxychlorinationprocess, these being mentioned hereinafter. Generally, the feed to theoxidative chlorination reactor is “fuel-rich,” meaning that a molarexcess of starting hydrocarbon is used relative to oxygen. Typically,the molar ratio of starting hydrocarbon to oxygen is greater than 2/1,preferably, greater than 4/1, and more preferably, greater than 5/1.Typically, the molar ratio of hydrocarbon to oxygen is less than 20/1,preferably, less than 15/1, and more preferably, less than 10/1.

[0027] Optionally, if desired, the feed, comprising startinghydrocarbon, source of halogen, and source of oxygen, can be dilutedwith a diluent or carrier gas, which may be any gas that does notsubstantially interfere with the oxidative chlorination process. Thediluent may assist in removing products and heat from the reactor and inreducing the number of undesirable side-reactions. Non-limiting examplesof suitable diluents include nitrogen, argon, helium, carbon monoxide,carbon dioxide, methane, and mixtures thereof. The quantity of diluentemployed typically ranges from greater than 10 mole percent, andpreferably, greater than 20 mole percent, to typically, less than 90mole percent, and preferably, less than 70 mole percent, based on thetotal moles of feed to the reactor, that is, total moles of startinghydrocarbon, source of halogen, source of oxygen, and diluent.

[0028] From the foregoing discussion the feedstream to the oxidativechlorination process comprises a mixture of hydrocarbon or halogenatedhydrocarbon, a source of chlorine, a source of oxygen, and optionally, adiluent or carrier gas. Accordingly, due diligence should be taken toavoid explosive mixtures. Towards this end, one skilled in the art wouldknow how to thoroughly evaluate the flammability limits of the specificfeedstream employed.

[0029] In a second aspect of the present invention, there is provided acomposition of matter which is useful as a catalyst in theaforementioned oxidative chlorination process. The composition comprisescopper dispersed on a porous rare earth halide support. The rare earthsare a group of 17 elements consisting of scandium (atomic number 21),yttrium (atomic number 39) and the lanthanides (atomic numbers 57-71)[James B. Hedrick, U.S. Geological Survey—Minerals Information—1997,“Rare-Earth Metals”]. Preferably, herein, the term is taken to mean anelement selected from lanthanum, cerium, neodymium, praseodymium,dysprosium, samarium, yttrium, gadolinium, erbium, ytterbium, holmium,terbium, europium, thulium, lutetium, and mixtures thereof. Preferredrare earth elements for use in the aforementioned oxidative chlorinationprocess are those which are typically considered as being single valencymetals. Catalytic performance of porous rare earth halide-supportedcatalysts using multi-valency metals appears to be less desirable thanthose using single valency metals. The rare earth element for thisinvention is preferably selected from lanthanum, neodymium,praseodymium, and mixtures thereof. Most preferably, the rare earthelement used in the catalyst support is lanthanum or a mixture oflanthanum with other rare earth elements.

[0030] Preferably, the support is represented by the formula MX₃ whereinM is at least one rare earth element lanthanum, cerium, neodymium,praseodymium, dysprosium, samarium, yttrium, gadolinium, erbium,ytterbium, holmium, terbium, europium, thulium, lutetium, and mixturesthereof; and wherein X is chloride, bromide, or iodide. More preferably,X is chloride, and the more preferred support is represented by theformula MCl₃, wherein M is defined hereinbefore. Most preferably, X ischloride and M is lanthanum, and the rare earth halide support islanthanum chloride.

[0031] Typically, the porous rare earth halide support has a BET surfacearea greater than 5 m²/g, preferably, greater than 10 m²/g, morepreferably, greater than 15 m²/g, even more preferably, greater than 20m²/g, and most preferably, greater than 30 m²/g. For these abovemeasurements, the nitrogen adsorption isotherm was measured at 77K andthe surface area was calculated from the isotherm data utilizing the BETmethod.

[0032] In a third aspect of the present invention, there is provided acomposition which is useful as a catalyst precursor to theaforementioned rare earth halide supported catalyst composition. Thecatalyst precursor comprises copper dispersed on a porous rare earthoxyhalide support. Preferably, the support is represented by the formulaMOX, wherein M is at least one rare earth element lanthanum, cerium,neodymium, praseodymium, dysprosium, samarium, yttrium, gadolinium,erbium, ytterbium, holmium, terbium, europium, thulium, lutetium, ormixtures thereof; and wherein X is chloride, bromide, or iodide. Morepreferably, the support is a rare earth oxychloride, represented by theformula MOCl, wherein M is defined hereinbefore. Most preferably, therare earth oxychloride is lanthanum oxychloride, LaOCl.

[0033] Typically, the porous rare earth oxyhalide support has a BETsurface area of greater than 12 m²/g, preferably, greater than 15 m²/g,more preferably, greater than 20 m²/g, and most preferably, greater than30 m²/g. Generally, the BET surface area is less than 200 m²/g. Inaddition, it is noted that the MOCl phases possess characteristic powderX-Ray Diffraction (XRD) patterns that are distinct from the MCl₃ phases.

[0034] In one preferred embodiment of this invention, the catalyst andcatalyst precursor compositions are essentially free of alumina, silica,aluminosilicate, and other conventional refractory support materials,for example, titania or zirconia. The term “essentially free” means thatthe conventional support material is present in a quantity less than 1weight percent, more preferably, less than 0.5 weight percent, and mostpreferably, less than 0.1 weight percent, based on the total weight ofthe catalyst or catalyst precursor composition and conventional supportmaterial.

[0035] In an alternative embodiment of this invention, the catalyst orcatalyst precursor composition, described hereinbefore (including copperon a rare earth halide or rare earth oxyhalide support material), may bebound to, extruded with, or deposited onto a conventional support, suchas alumina, silica, silica-alumina, porous aluminosilicate (zeolite),silica-magnesia, bauxite, magnesia, silicon carbide, titanium oxide,zirconium oxide, zirconium silicate, or combination thereof. In thisembodiment, the conventional support is used in a quantity greater than1 weight percent, but less than 50 weight percent, preferably, less than30 weight percent, more preferably, less than 20 weight percent, basedon the total weight of the catalyst or catalyst precursor compositionand conventional support. Even when a conventional support is present,it is still a fact that the copper is predominantly deposited on therare earth oxyhalide or halide support and that the rare earth oxyhalideor halide support remains the predominant bulk material.

[0036] It may also be advantageous to include other elements within thecatalyst. For example, preferable elemental additives include alkali andalkaline earths, boron, phosphorous, sulfur, germanium, titanium,zirconium, hafnium, and combinations thereof. These elements can bepresent to alter the catalytic performance of the composition or toimprove the mechanical properties (for example, attrition-resistance) ofthe material. In a most preferred embodiment, however, the elementaladditive is not aluminum or silicon. The total concentration ofelemental additives in the catalyst is typically greater than 0.01weight percent and typically less than 20 weight percent, based on thetotal weight of the catalyst.

[0037] In light of the disclosure herein, those of skill in the art willrecognize alternative methods for preparing the support composition ofthis invention. A method currently felt to be preferable for forming thecomposition comprising the porous rare earth oxyhalide (MOX) comprisesthe following steps: (a) preparing a solution of a halide salt of therare earth element or elements in a solvent comprising either water, analcohol, or mixtures thereof; (b) adding a base to cause the formationof a precipitate; and (c) collecting and calcining the precipitate inorder to form the MOX. Preferably, the halide salt is a rare earthchloride salt, for example, any commercially available rare earthchloride. Typically, the base is a nitrogen-containing base selectedfrom ammonium hydroxide, alkyl amines, aryl amines, arylalkyl amines,alkyl ammonium hydroxides, aryl ammonium hydroxides, arylalkyl ammoniumhydroxides, and mixtures thereof. The nitrogen-containing base may alsobe provided as a mixture of a nitrogen-containing base with other basesthat do not contain nitrogen. Preferably, the nitrogen-containing baseis ammonium hydroxide or tetra(alkyl)ammonium hydroxide, morepreferably, tetra(C₁₋₂₀ alkyl)ammonium hydroxide. Porous rare earthoxychlorides may also be produced by appropriate use of alkali oralkaline earth hydroxides, particularly, with the buffering of anitrogen-containing base, although caution should be exercised to avoidproducing the rare earth hydroxide or oxide. The solvent in Step (a) ispreferably water. Generally, the precipitation is conducted at atemperature greater than 0° C. Generally, the precipitation is conductedat a temperature less than 200° C., preferably, less than 100° C. Theprecipitation is conducted generally at ambient atmospheric pressure,although higher pressures may be used, as necessary, to maintain liquidphase at the precipitation temperature employed. The calcination istypically conducted at a temperature greater than 200° C., preferably,greater than 300° C., and less than 800° C., preferably, less than 600°C. Production of mixed carboxylic acid and rare earth chloride saltsalso can yield rare earth oxychlorides upon appropriate decomposition.

[0038] A method currently felt to be preferable for forming the catalystcomposition comprising the rare earth halide (MX₃) comprises thefollowing steps: (a) preparing a solution of a halide salt of the rareearth element or elements in a solvent comprising either water, analcohol, or mixtures thereof; (b) adding a base to cause the formationof a precipitate; (c) collecting and calcining the precipitate; and (d)contacting the calcined precipitate with a halogen source. Preferably,the rare earth halide is a rare earth chloride salt, such as anycommercially available rare earth chloride. The solvent and base may beany of those mentioned hereinbefore in connection with the formation ofMOX. Preferably, the solvent is water, and the base is anitrogen-containing base. The precipitation is generally conducted at atemperature greater than 0° C. and less than 200° C., preferably lessthan 100° C., at ambient atmospheric pressure or a higher pressure so asto maintain liquid phase. The calcination is typically conducted at atemperature greater than 200° C., preferably, greater than 300° C., butless than 800° C., and preferably, less than 600° C. Preferably, thehalogen source is a hydrogen halide, such as hydrogen chloride, hydrogenbromide, or hydrogen iodide. More preferably, the halogen source ishydrogen chloride. The contacting with the halogen source is typicallyconducted at a temperature greater than 100° C. and less than 500° C.Typical pressures for the contacting with the source of halogen rangefrom ambient atmospheric pressure to pressures less than 150 psia (1,034kPa).

[0039] As noted hereinabove, the rare earth oxyhalide support (MOX) canbe converted into the rare earth halide support (MX₃) by treating theMOX support with a source of halogen. Since the oxidative chlorinationprocess of this invention requires a source of chlorine, it is possibleto contact the Cu-loaded MOCl support with a source of chlorine in situin the oxidative chlorination reactor to form the MCl₃-supported Cucatalyst. The in situ method of forming the catalyst can be generalizedto halogen species other than chlorine. The porous rare earth oxyhalidematerial also finds utility as a catalyst support, even under conditionswhich do not convert the oxyhalide to the halide.

[0040] The porous oxychloride material, MOX, and the fully chloridedmaterial, MX₃, can be used in any process wherein a catalyst support orcarrier is required. The porous rare earth oxyhalide or halide can beused as a support for any catalytic metal or metallic ion in thePeriodic Table of the Elements, as well as any organic or non-metallicinorganic catalyst component. Suitable metals and metallic ions can beselected from Groups 1A, 2A, 3B, 4B, 5B, 6B, 7B, 8B, 1B, 2B, 3A, 4A, and5A of the Periodic Table, as referenced for example, in Chemistry, by S.Radel and M. Navidi, West Publishing Company, New York, 1990. Preferredprocesses include catalytic processes wherein a rare earth element isdesirable as a catalyst or catalyst promoter, including withoutlimitation, oxidations, reductions, hydrogenations, isomerizations,aminations, cracking processes, alkylations, esterifications, and otherhydrocarbon conversion processes, such as Fischer-Tropsch syntheses. Theoxyhalogenation process illustrated herein is only one use for the novelsupports described herein; but this illustration should not limit theuse of these supports in other applications. Any contacting method canbe used to deposit or disperse the catalytic component(s) onto theporous supports of this invention, including without limitation,impregnation, ion-exchange, deposition-precipitation, co-precipitation,and vapor deposition. These contacting methods are well-described in thecatalysis art, for example, as may be found in Fundamentals ofIndustrial Catalytic Properties, by Robert J. Farrauto and Calvin H.Bartholomew, Blackie Academic & Professional, an Imprint of Chapman &Hall, London, 1997.

[0041] For the instant oxidative chlorination application, thedeposition of copper onto the catalyst precursor support, MOX, orcatalyst support, MX₃, can be accomplished by co-precipitating thecopper and lanthanum from a solution containing a base in a mannersimilar to that noted hereinabove in connection with the formation ofthe support. Alternatively, the copper can be deposited from acopper-containing solution by impregnation or ion-exchange, or by vapordeposition from a volatile copper compound. Typically, the copperloading is greater than 0.01 weight percent, preferably, greater than 1weight percent, and more preferably, greater than 5 weight percent,based on the total weight of the catalyst or catalyst precursorcomposition. Typically, the copper loading is less than 30 weightpercent, preferably, less than 20 weight percent, and more preferably,less than 15 weight percent, based on the total weight of the catalystor catalyst precursor composition.

[0042] The oxidative chlorination process of this invention can beconducted in a reactor of any conventional design suitable, preferably,for gas phase processes, including batch, fixed bed, fluidized bed,transport bed, continuous and intermittent flow reactors. Any processconditions (for example, molar ratio of feed components, temperature,pressure, gas hourly space velocity), can be employed, provided that thedesired halocarbon product, preferably chlorocarbon, is selectivelyobtained. Typically, the process temperature is greater than 150° C.,preferably, greater than 200° C., and more preferably, greater than 250°C. Typically, the process temperature is less than 500° C., preferably,less than 425° C., and more preferably, less than 350° C. Ordinarily,the process will be conducted at atmospheric pressure or a higherpressure. Typically then, the pressure will be equal to or greater than14 psia (101 kPa), but less than 150 psia (1,034 kPa). Typically, thetotal gas hourly space velocity (GHSV) of the reactant feed(hydrocarbon, source of halogen, source of oxygen, and any optionaldiluent) will vary from greater than 10 ml total feed per ml catalystper hour (h⁻¹), preferably, greater than 100 h⁻¹, to less than 50,000h⁻¹, and preferably, less than 10,000 h⁻¹.

[0043] The chlorocarbon formed in the process of this invention containsa greater number of chlorine substituents than was present in thestarting hydrocarbon or starting chlorinated hydrocarbon. The preferredchlorocarbon product is 1,2-dichloroethane. The oxidative chlorinationprocess of this invention produces oxygenated chlorocarbon by-products,such as chloral, in concentrations which are lower by a factor of atleast 20 mole percent to as much as 90 mole percent, as compared withprior art oxychlorination processes. Likewise, the oxychlorinationprocess of this invention produces CO_(x) oxygenates (CO and CO₂) in asignificantly lower quantity than prior art oxychlorination processes,typically in a quantity lowered by a factor of 10.

[0044] The following examples are provided as an illustration of theprocess of this invention, the catalyst and catalyst precursorcompositions of this invention, and the novel supports of thisinvention. These examples should not be construed as limiting theinventions in any manner. In light of the disclosure herein, those ofskill in the art will recognize alternative embodiments, for example ofreactants, process conditions, catalyst species, and support species,which all fall within the scope of this invention.

EXAMPLE 1

[0045] A catalyst precursor composition comprising copper on a porouslanthanum oxychloride support was prepared as follows. Lanthanumchloride (LaCl₃. 7 H₂O, 15.0 g) was dissolved in deionized water (150ml). Ammonium hydroxide (6 M, 20 ml) was added to the lanthanum chloridesolution quickly with stirring, resulting in a white precipitate. Themixture was centrifuged and the excess liquid decanted yielding alanthanum-containing gel. Cupric chloride (CuCl₂.2 H₂O, 0.689 g) wasdissolved in ammonium hydroxide (6 M) by using just enough solution todissolve the copper salt. The copper solution was added to thelanthanum-containing gel. The gel was stirred until a homogeneouslycolored, dark blue precipitate was obtained. The precipitate wascalcined at 400° C. for 4 hours to yield a composition (5.35 g)comprising copper (10 mole percent) dispersed on a porous lanthanumoxychloride support. X-ray diffraction data indicated the presence of aquasi-crystalline form of lanthanum oxychloride. The surface area of thecatalyst was 25.8 m²/g, as measured by the BET method.

EXAMPLE 2

[0046] The catalyst precursor composition of Example 1 was converted insitu into a catalyst composition of this invention, comprising copperdispersed on a porous lanthanum chloride support. The catalyst was thenevaluated in the oxychlorination of ethylene. A tubular reactor wasloaded with a mixture of catalyst precursor material (0.3208 g,) fromExample 1 and a low surface area alumina diluent (Norton SA5225 alumina;2.3258 g). The catalyst precursor was dried under a flow of argon at200° C. for 1 h, then converted in situ to the active catalyst bytreating the precursor with a mixture of 44.4 mole percent hydrogenchloride, 8.6 mole percent oxygen, and 47.0 mole percent argon for 10minutes at 250° C. and with a weight hourly space velocity of 22 h⁻¹.The weight hourly space velocity is the mass flow rate divided by theweight of the catalyst tested.

[0047] An oxychlorination feed was started comprising 18.2 mole percentethylene, 36.3 mole percent hydrogen chloride, 7.0 mole percent oxygen,and 38.5 mole percent argon at 250° C. and a weight hourly spacevelocity of 26 h⁻¹. The reaction was continued for 30 minutes at 250°C., and the temperature was changed to 300° C. under the same feedconditions. Results are set forth in Table 1. The measurements at 300°C. in Table 1 were taken using an average of the performance at 300° C.during a 15 minute period. The reaction feed composition was changed tohave a lower oxygen content, with 16.7 mole percent ethylene, 33.3 molepercent hydrogen chloride, 4.3 mole percent oxygen, and 45.7 molepercent argon at a weight hourly space velocity of 28 h⁻¹. Thetemperature was raised to 350° C. over 30 minutes and then to 400° C.over 30 minutes. Data in Table 1 taken at 400° C. were an average of thecomposition during a 15 minute period at 400° C. The gaseous effluentfrom the reactor was analyzed by mass spectrometry using a calibrationmatrix to deconvolute the gas composition from the data. Chloral wasestimated by monitoring the mass peak at 82 a.m.u. Process conditionsand results are set forth in Table 1. TABLE 1 Oxychlorination ofEthylene to Ethylene Dichloride (EDC)^(a) WHSV T EDC Chloral ExampleCatalyst (h⁻¹) (° C.) (ml/min) (counts) 2 Cu/LaCl₃ 26 300 4.02 8 ″ ″ 28400 8.86 700 CE-1 Cu/K/Al₂O₃ 78 300 2.84 160 ″ ″ 87 400 7.58 900

[0048] From Table 1 it is seen that the novel catalyst comprising copperon a porous lanthanum chloride support is capable of oxychlorinatingethylene in the presence of hydrogen chloride and oxygen to1,2-dichloroethane. As an advantage, only a low level of chloral isproduced, especially at the lower reaction temperature of 300° C.

Comparative Experiment 1 (CE-1)

[0049] An oxychlorination of ethylene was conducted in the mannerdescribed in Example 2, with the exception that a comparativeoxychlorination catalyst containing copper (4 weight percent) andpotassium (1.5 weight percent) supported on alumina was used in place ofthe catalyst of Example 2. The comparative catalyst (0.1046 g) was mixedwith alumina diluent (2.6639 g), and the mixture was loaded into areactor similar to that in Example 2. The oxychlorination process wasoperated as in Example 2, with the process conditions and results setforth in Table 1. When Comparative Experiment 1 is compared with Example2 at similar process conditions, it is seen that the catalyst of theinvention, which comprised copper dispersed on a porous lanthanumchloride support, achieved a higher productivity to 1,2-dichloroethaneat a significantly lower selectivity to impurity chloral, as comparedwith the comparative catalyst.

EXAMPLE 3

[0050] The catalyst precursor composition of Example 1 was loaded into afixed bed reactor, converted into an active catalyst comprising copperon a porous lanthanum chloride support by the in situ method describedin Example 2, then tested in the oxychlorination of ethylene. A gas feedcontaining ethylene (53.75 mole percent), oxygen (14.61 mole percent),and hydrogen chloride (29.26 mole percent) was passed over the catalystat atmospheric pressure and at 300° C. Flows were adjusted to yield 50percent conversion of oxygen. The catalyst produced 1,2-dichloroethaneas the dominant product. The total carbon oxides (CO_(x)) produced wasonly 0.8 mole percent of the exit gas. Additionally, since the catalystwas water soluble, the spent catalyst could easily be removed from thereactor and supportive equipment, such as filters and transfer lines, bya simple water wash.

Comparative Experiment 2 (CE-2)

[0051] Example 3 was repeated using a comparative oxychlorinationcatalyst in place of the catalyst of Example 3. The comparativecatalyst, similar to the catalyst of experiment CE-1, contained copper(5.7 weight percent) and potassium (1.75 weight percent) supported onalumina. The comparative catalyst produced 1,2-dichloroethane as thedominant product; however, the total carbon oxides (CO_(x)) produced was4.5 mole percent of the exit gas. When Comparative Experiment 2 wascompared with Example 3, it was seen that under similar processconditions the catalyst of the invention produced significantly lesscarbon oxides than the comparative catalyst.

What is claimed is:
 1. A composition of matter comprising copperdispersed on a porous rare earth halide support.
 2. The composition ofclaim 1 wherein the porous rare earth halide support has a BET surfacearea greater than 5 m²/g.
 3. The composition of claim 2 wherein theporous rare earth halide support has a BET surface area greater than 15m²/g.
 4. The composition of claim 1 wherein the rare earth halidesupport is represented by the formula MX₃, wherein M is at least onerare earth lanthanum, cerium, neodymium, praseodymium, dysprosium,samarium, yttrium, gadolinium, erbium, ytterbium, holmium, terbium,europium, thulium, lutetium, or mixtures thereof, or wherein X ischloride, bromide, or iodide.
 5. The composition of claim 4 wherein X ischloride, M is lanthanum, and the rare earth halide support is lanthanumchloride.
 6. A composition of matter comprising copper dispersed on aporous rare earth oxyhalide support.
 7. The composition of claim 6wherein the porous rare earth oxyhalide support has a BET surface areagreater than 12 m²/g.
 8. The composition of claim 7 wherein the porousrare earth oxyhalide support has a BET surface area greater than 20m²/g.
 9. The composition of claim 7 wherein the rare earth oxyhalidesupport is represented by the formula MOX, wherein M is at least onerare earth lanthanum, cerium, neodymium, praseodymium, dysprosium,samarium, yttrium, gadolinium, erbium, ytterbium, holmium, terbium,europium, thulium, lutetium, or mixtures thereof; or wherein X ischloride, bromide, or iodide.
 10. The composition of claim 9 wherein Xis chloride, M is lanthanum, and the rare earth oxyhalide support islanthanum oxychloride.
 11. A method of using a porous rare earth halideas a catalyst support comprising depositing one or more catalyticcomponents onto the porous rare earth halide support.
 12. The method ofclaim 11 wherein one or more metals or metallic ions are deposited ontothe porous rare earth halide support, the metals or metallic ions beingthe elements of Groups 1A, 2A, 3B, 4B, 5B, 6B, 7B, 8B, 1B, 2B, 3A, 4A,or 5A of the Periodic Table.
 13. A method of using a porous rare earthoxyhalide as a catalyst support comprising depositing one or morecatalytic components onto the porous rare earth oxyhalide support. 14.The method of claim 13 wherein one or more metals or metallic ions aredeposited onto the rare earth oxyhalide support, the metals or metallicions being the elements of Groups 1A, 2A, 3B, 4B, 5B, 6B, 7B, 8B, 1B,2B, 3A, 4A, or 5A of the Periodic Table.
 15. The method of claim 13wherein after one or more catalytic components are deposited onto therare earth oxyhalide support, the support is contacted with a source ofhalogen under conditions sufficient to convert the rare earth oxyhalidesupport to a rare earth halide support.
 16. The method of claim 15wherein the source of halogen is hydrogen chloride or molecularchlorine.